In recent years, tires have been provided with a circumferential reinforcing layer in the belt layer in order to reduce radial growth of tires. The technology described in Japanese Unexamined Patent Application Publication No. 2001-253211A is a conventional pneumatic tire that is configured in this manner. This conventional pneumatic tire is provided with protrusions in the groove bottoms of the circumferential main grooves in order to prevent damage to the groove bottoms of the circumferential main grooves, and increase the tire cracking resistance performance.